FN Archimer Export Format
PT J
TI Accumulation of Fe oxyhydroxides in the Peruvian oxygen deficient zone implies non-oxygen dependent Fe oxidation
BT 
AF HELLER, Maija Iris
   LAM, Phoebe J.
   MOFFETT, James W.
   TILL, Claire P.
   LEE, Jong-Mi
   TONER, Brandy M.
   MARCUS, Matthew A.
AS 1:1;2:1;3:2;4:1;5:1;6:3;7:4;
FF 1:;2:;3:;4:;5:;6:;7:;
C1 Univ Calif Santa Cruz, Dept Ocean Sci, Santa Cruz, CA 95064 USA.
   Univ Southern Calif, Dept Biol Sci, Marine Environm Biol, Los Angeles, CA 90089 USA.
   Univ Minnesota Twin Cities, Dept Soil Water & Climate, St Paul, MN 55108 USA.
   Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA.
C2 UNIV CALIF SANTA CRUZ, USA
   UNIV SOUTHERN CALIF, USA
   UNIV MINNESOTA, USA
   UNIV CALIF BERKELEY, USA
IF 4.69
TC 56
UR https://archimer.ifremer.fr/doc/00386/49714/50242.pdf
LA English
DT Article
DE ;Oxygen minimum zone;Oxygen deficient zone;OMZ;ODZ;Fe redox cycling;Synchrotron XAS
AB Oxygen minimum zones (OMZs) have been proposed to be an important source of dissolved iron (Fe) into the interior ocean. However, previous studies in OMZs have shown a sharp decrease in total dissolved Fe (dFe) and/or dissolved Fe(II) (dFe(II)) concentrations at the shelf-break, despite constant temperature, salinity and continued lack of oxygen across the shelf-break. The loss of both total dFe and dFe(II) suggests a conversion of the dFe to particulate form, but studies that have coupled the reduction-oxidation (redox) speciation of both dissolved and particulate phases have not previously been done. Here we have measured the redox speciation and concentrations of both dissolved and particulate forms of Fe in samples collected during the U.S. GEOTRACES Eastern tropical Pacific Zonal Transect (EPZT) cruise in 2013 (GP16). This complete data set allows us to assess possible mechanisms for loss of dFe. We observed an offshore loss of dFe(II) within the oxygen deficient zone (ODZ), where dissolved oxygen is undetectable, accompanied by an increase in total particulate Fe (pFe). Total pFe concentrations were highest in the upper ODZ. X-ray absorption spectroscopy revealed that the pFe maximum was primarily in the Fe(III) form as Fe(III) oxyhydroxides. The remarkable similarity in the distributions of total particulate iron and nitrite suggests a role for nitrite in the oxidation of dFe(II) to pFe(III). We present a conceptual model for the rapid redox cycling of Fe that occurs in ODZs, despite the absence of oxygen. 
PY 2017
PD AUG
SO Geochimica Et Cosmochimica Acta
SN 0016-7037
PU Pergamon-elsevier Science Ltd
VL 211
UT 000405786800011
BP 174
EP 193
DI 10.1016/j.gca.2017.05.019
ID 49714
ER

EF